/Engine/Plugins/Runtime/MeshModelingToolset/Source/ModelingComponents/Public/Selection/PolygonSelectionMechanic.h
Convert the Active Selection to a Triangle-topology FGeometrySelection, with optional CompactMaps
void GetSelection_AsTriangleTopology ( [UE::Geometry::FGeometrySelection](API\Plugins\DynamicMesh\Selections\FGeometrySelection) & SelectionOut, const [FCompactMaps](API\Runtime\GeometryCore\Util\FCompactMaps) * CompactMapsToApply ) const